A unique presentation of 5-fluorouracil (5-FU) induced cerebral encephalopathy

Transient Coma and Signs of Encephalopathy Related to 5-Fluorouracil and Carboplatin: A Case Report

Chemotherapy-related encephalopathy is a rare but severe side effect of cancer therapy. Few reports exist on the course of encephalopathy due to 5-fluorouracil (5FU)/carboplatin treatment. Here, we report on a patient in his 70s, who received first-line palliative treatment with carboplatin followed by continuous infusion of 5FU against a metastasized cancer of the base of the tongue. During the first 5FU infusion, the patient developed a coma with sudden onset. In contrast to earlier reports of 5FU-induced encephalopathy, serum ammonium levels were near-normal, despite a slightly increased bilirubin. The electroencephalogram showed signs of general encephalopathy, for which no other probable cause than chemotherapy could be identified. Based on historical reports, the patient's encephalopathy was likely due to 5FU treatment rather than carboplatin. While initially in a coma with a Glasgow Coma Scale score of three, the patient regained consciousness within 3 days of supportive therapy. This case highlights the potentially benign clinical course of 5FU-induced encephalopathy, characterized by fulminant clinical deterioration and quick recovery. Such a rapid deterioration in a palliative setting can pose a clinical dilemma, where invasive treatments such as intubation must be weighed against a limited prognosis, for which this case may provide guidance.

Leukoencephalopathy with transient splenial lesions related to 5-fluorouracil or capecitabine

BACKGROUND

5-Fluorouracil (5-FU) and its oral prodrug capecitabine have been rarely but consistently associated with acute central nervous system toxicity, including transient leukoencephalopathies involving the splenium of the corpus callosum.

METHODS

We performed a retrospective search in the French Pharmacovigilance database (FPDB) (January 1985-July 2020) for adult patients affected by solid cancers who developed acute toxic leukoencephalopathies with splenial lesions following treatment with 5-FU or capecitabine. A comprehensive review of the literature helped to circumstantiate our findings.

RESULTS

Our research in the FPDB identified six patients who, within 3 days from their first cycle of 5-FU or capecitabine, developed acute neurological symptoms, including gait ataxia (n = 4), dysarthria (n = 3), dysmetria (n = 2), headache (n = 2), and confusion (n = 2). Brain magnetic resonance imaging (MRI) showed T2/FLAIR (fluid-attenuated inversion recovery) hyperintensities in the corpus callosum, with diffusion restriction and no contrast enhancement, generally accompanied by additional alterations in the bilateral supratentorial white matter (n = 5). All patients discontinued the agent supposedly responsible for the toxicity and experienced full recovery after a median of 8.5 days from symptom onset. Control MRI showed a progressive normalization of acute MRI abnormalities. Literature review identified 26 cases with similar clinical and paraclinical characteristics. A single patient from the literature resumed 5-FU at a lower dose, with no recurrent toxicity.

CONCLUSIONS

5-FU and capecitabine might be responsible for acute leukoencephalopathies with transient splenial lesions that are generally reversible upon drug discontinuation. Resuming the agent responsible for toxicity might be feasible in selected cases, after having excluded dihydropyrimidine dehydrogenase deficiency, if expected benefits outweigh the risks.